Gearing.



' T. A. MUGINLEY.

emma. APPLICATION FILED JULY 27, 1912. I

Patented Dec. 17,1912.

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T. A.` MoGINLEY.

asume. APPLIOATIOI FILED JULY 27, 1912 Patented Dec. 17,1912.

2 SHEETS-SHEET 2'.

UNTTED sTATEs PATENT OFFICE.

THOMAS A. MCGINLEY, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR-TO THE DUFF MANUFACTURING COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF. PENNSYLVANIA.

GEARING.

Patented Dec.17,1912.

Application filed July 27, 1912. Serial No. 711,820.

To a7] whom 'it may concern Beit known that I, THOMAS A.. MoGlNLEY,

a resident of Pittsburgh, Allegheny county, Pennsylvania, have-invented a new and useful Improvement in Gearing, of which |`the following isa full, clear, and 'exact description, reference being had to the accompanying drawings, forming part of'this specification, in which- Figure 1 is a vertical section of onev form .of lifting jack embodying my invention;

Fig. 2 is a view, partly in plan and partly in section of the nut member; and Fig. 3 is a. face view of one section of the nut member.

My invention has relation to gearing particularly adapted to lifting jacks, and more especially to that class of lifting jacks .which are commonly known as high-speed screw picks.

' embodiment thereof, and which will now be described.

In these drawings-LI have shown the invention as applied to one particular type of screw jack, but I desire it understood that the inventionis equally applic-able t-o screw jacks of other specific kinds, as well as gearing generally where high power is obtained by means of a screw. v

In those drawings, the numerati). designatos the base of the jack, having an upwardly extending cylinder 3 provided with a head 4, in .which'is formed' a cavity for a central nut 5. 6 is a quick-pitch screw stem, which extends down through the nut and. has rotary engagement at its low-er end with a piston 7. This piston works within the lower dash-pot-forming portion of the cylinder 3, and is provided with the by-pass opening 8 therethrough controlled by an 1.1pwa-dly seating ball balve 9. The cylinder devices for thevhead, which devices constitute no part of the present invention, and which may be of any suitable character. 15 is a bevel gear wheel secured to the upper portion of the shaft or stem 6, and which is driven by a bevel gear wheel 16 on an actuating shaft 17. I

18 designates a b-y-pass passage for the dashpot liquid, and which is arranged to be controlled byan adjustable valve 19.

The nut 5 is provided with a plurality of pins 20 secured in holes drilled or bored therein, t-hese holes being arranged in heli.- cal lines corresponding to'the pitchof t-he threads of the screw shaft or stem 6. On the projecting inner end of each of these pins 20 is journaled an anti-friction roller 21.

` These rollers have coned surfaces, which are radial with respect to thel axial center of the shaft 6, and which are adapted to, engage the threads of said shaft in the manner clearly shown in F ig. l.

The jack is operated in the usual manner of these jacks, the load beinglifted by actuating the screw shaft 17. When it is desired to allow the load to move down under they 'anti-friction rollers arranged as described,

whereby the entire frictional engagement between the screw stem or shaft and the nut takes place ont-bese rollers, friction between the parts is reduced to a minimum.

What I claiin'is:-- n 1. A lifting member having a helical screw stem or'shaft, and a cylinder member having a nut provided with a plurality of helically arranged anti-friction rollers engaged in the threads of the nut; substantially as described.

l 2. The combination with a helical screw member and a relatively fixed nut, the lat-ter ternal anti-friction rollers; substantially as" described.

3. The combination With a helical sereW member and a relatively fixed nut, the latter having a plurality of helically arranged internal anti-friction rollers, the surfaces of said rollers being eoned; substantially as 10 described. y

' In testimony whereof, .I have hereunto set my hand.

Witnesses: I

GEO. J. TAYLOR, A. F. Tlnrrs. 

